yahoo-eng-team team mailing list archive

[Rossella Sblendido <rsblendido@xxxxxxxx>]

Public bug reported:

On a cloud running Liberty, a VM is assigned a floating IP. The VM is
live migrated and the floating IP is no longer reachable from outside
the cloud. Steps to reproduce:

1) spawn a VM
2) assign a floating IP
3) live migrate the VM
4) ping the floating IP from outside the cloud

the problem seems to be that both the node that was hosting the VM
before the migration and the node that hosts it now answers the ARP
request:

admin:~ # arping -I eth0 10.127.128.12 
ARPING 10.127.128.12 from 10.127.0.1 eth0
Unicast reply from 10.127.128.12 [FA:16:3E:C8:E6:13]  305.145ms
Unicast reply from 10.127.128.12 [FA:16:3E:45:BF:9E]  694.062ms
Unicast reply from 10.127.128.12 [FA:16:3E:45:BF:9E]  0.964ms

on the compute that was hosting the VM:

root:~ # sudo ip netns exec fip-c622fafe-c663-456a-8549-ebd3dbed4792 ip route
default via 10.127.0.1 dev fg-c100b010-af 
10.127.0.0/16 dev fg-c100b010-af  proto kernel  scope link  src 10.127.128.3 
10.127.128.12 via 169.254.31.28 dev fpr-7d1a001a-9 

On the node that it's hosting the VM:

root:~ # sudo ip netns exec fip-c622fafe-c663-456a-8549-ebd3dbed4792 ip route
default via 10.127.0.1 dev fg-e532a13f-35 
10.127.0.0/16 dev fg-e532a13f-35  proto kernel  scope link  src 10.127.128.8 9 
10.127.128.12 via 169.254.31.28 dev fpr-7d1a001a-9 

the entry "10.127.128.12" is present in both nodes.  That happens
because when the VM is migrated no clean up is triggered on the source
host. Restarting the l3 agent fixes the problem because the stale entry
is removed.

** Affects: neutron
     Importance: High
     Assignee: Rossella Sblendido (rossella-o)
         Status: New

** Changed in: neutron
   Importance: Undecided => High

** Changed in: neutron
     Assignee: (unassigned) => Rossella Sblendido (rossella-o)

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to neutron.
https://bugs.launchpad.net/bugs/1585165

Title:
  floating ip not reachable after vm migration

Status in neutron:
  New

Bug description:
  On a cloud running Liberty, a VM is assigned a floating IP. The VM is
  live migrated and the floating IP is no longer reachable from outside
  the cloud. Steps to reproduce:

  1) spawn a VM
  2) assign a floating IP
  3) live migrate the VM
  4) ping the floating IP from outside the cloud

  the problem seems to be that both the node that was hosting the VM
  before the migration and the node that hosts it now answers the ARP
  request:

  admin:~ # arping -I eth0 10.127.128.12 
  ARPING 10.127.128.12 from 10.127.0.1 eth0
  Unicast reply from 10.127.128.12 [FA:16:3E:C8:E6:13]  305.145ms
  Unicast reply from 10.127.128.12 [FA:16:3E:45:BF:9E]  694.062ms
  Unicast reply from 10.127.128.12 [FA:16:3E:45:BF:9E]  0.964ms

  on the compute that was hosting the VM:

  root:~ # sudo ip netns exec fip-c622fafe-c663-456a-8549-ebd3dbed4792 ip route
  default via 10.127.0.1 dev fg-c100b010-af 
  10.127.0.0/16 dev fg-c100b010-af  proto kernel  scope link  src 10.127.128.3 
  10.127.128.12 via 169.254.31.28 dev fpr-7d1a001a-9 

  On the node that it's hosting the VM:

  root:~ # sudo ip netns exec fip-c622fafe-c663-456a-8549-ebd3dbed4792 ip route
  default via 10.127.0.1 dev fg-e532a13f-35 
  10.127.0.0/16 dev fg-e532a13f-35  proto kernel  scope link  src 10.127.128.8 9 
  10.127.128.12 via 169.254.31.28 dev fpr-7d1a001a-9 

  the entry "10.127.128.12" is present in both nodes.  That happens
  because when the VM is migrated no clean up is triggered on the source
  host. Restarting the l3 agent fixes the problem because the stale
  entry is removed.

To manage notifications about this bug go to:
https://bugs.launchpad.net/neutron/+bug/1585165/+subscriptions